Substituted benzamidopiperidinopropanes



SUBSTITUTED BENZAMIDOPIPERIDINO- PROPANES Albert Pohland, Indianapolis, Ind., assignor to Eli Lilly illllld Company, Indianapolis, Ind., a corporation of diana No Drawing. Original application December 9, 1953, Serial No. 397,261. Divided and this application October 24, 1955, Serial No. 542,501

2 Claims. (Cl. 260-494) nited States Patent are soluble in the common polar organic solvents. The acid addition salts of those bases are in general watersoluble, crystalline substances.

The new substituted benzamidopiperidinopropanes and their salts are local anesthetics characterized by stability, lack of irritation and long duration of action. For therapeutic use, the compounds can be advantageously utilized as water solutions of the acid addition salts, or the salts or bases can be incorporated into various pharmaceutical extending media such as ointments, solutions, jellies, oils, lotions, suspending media and the like.

The new compounds can be prepared by methods known to the art, exemplified by the following series of equations, in which R and R1 have the same significance as This invention relates to substituted benzamidopropylhereinab'ove.

amines and more particularly to substituted l-benzamido- 3-piperidinopropanes and their acid addition salts, and to the preparation thereof.

The bases of the substituted benzamidopiperidinopropanes of the present invention may be represented by the formula /CHr-CH RQ-G oNHdH-oHomN cm R1 CHg-O 1 Referring to the equations, it will be seen that a substituted piperidinopropiophenone is treated with hydroxylamine to produce the corresponding oXime, which is hydrogenated to form a substituted phenylpiperidinopropylamine. The piperidinopropylamine is reacted with a substituted benzoyl chloride to form the correspondingly substituted benzamidopiperidinopropane.

As will be evident, the compounds contain a basic nitrogen atom, Which can react with acids to form acid addition salts. Such salts are readily prepared by the usual methods of the art, e. g., the reaction of stoichiometrical- 1y equivalent amounts of the desired base and a selected acid in a mutual inert solvent. Examples of acids which are suitable for the preparation of acid addition salts of the invention are inorganic acids, for example, hydrochloric, nitric, sulfuric, phosphoric, and the like acids; and organic acids, for example, benzoic, acetic, salicylic, propionic, maleic, citric and the like acids. The preferred salts are the pharmaceutically useful salts, i. e., acid addition salts which are not materially more toxic or irritatvmonium hydroxide.

Preparation of 1-benzamid0-I-phenyl-3-piperidinopropane hydrochloride A mixture of 1.01.5 g. of fi-piperidinopropiophenone hydrochloride, prepared by the method of Adams, Organic Reactions 1, 329 (1942), 31.4 g. of hydroxylamine hydrochloride, 33.6 g. of sodium bicarbonate and 200 ml. of water was allowed to stand at room temperature overnight. A solution of 43 g. of sodium hydroxide in 43 ml. of water was added to the reaction mixture and after cooling, the precipitated fi-piperidinopropiophenone oxime was removed by filtration. After recrystallization from methanol, the fl-piperidinopropiophenone oxime thusprepared melted at 152-153 C.

Analysis.Cal=culated for Found: N, 11.75.

fl-Piperidinopropiophenone oxime hydrochloride melted at about 190-191 C. after recrystallization from methanol-ethyl acetate mixture.

Analysis.-Calculated for C14H21N2OC1: N, 10.40; Cl, 13.19. Found: N, 10.00; Cl, 13.13.

C14H20N2O: N, 12.07.

A mixture of g. of Raney nickel catalyst, 81.5 g. of

ti-piperidiuopropiophenone oxime, 200 ml. of ethanol and 75 ml. of liquid ammonia was placed in an autoclave, and reduced under 1400 lbs. pressure of hydrogen for one hour at 70 to 110 C. The reaction mixture was filtered and fractionally distilled under reduced pressure and the 1-phenyl-3-piperidinopropylamine formed in the reaction distilled at 133-134 C. at a pressure of 1 mm. of mercury. The index of refraction at C. was 1.5231.

Analysis.Calculated for C14H22N2: N, 12.83. Found: N, 12.32.

The maleate salt of 1-phenyl-3-piperidinopropylamine melted at about ISO-151 C.

Analysis.Calculated for CazHsoNzOa: C, 58.65; H, 6.71; N, 6.22. Found: C, 58.88; H, 6.78; N, 6.48.

A mixture of 24 g. of l-phenyl-3-piperidinopropylamine, 24 ml. of benzoyl chloride, 300 ml. of benzene and 45 ml. of dry pyridine was allowed to stand at room temperature for about sixteen hours. A suflicient amount of ethyl ether was thereafter added to bring about complete precipitation of the l-benzamido-1-phenyl-3-piperidinopropane hydrochloride formed in the reaction. The precipitate was removed by filtration and recrystallized from a mixture of isopropanol and ether.

l-benzamido-l-phenyl-3-piperidinopropane hydrochloride thus prepared melted at about 188-189" C.

Analysis.Calculated for C21H27N2OC1: N, 7.81; CI, 9.88. Found: N, 7.90; CI, 9.92.

EXAMPLE 2 Preparation of 1-benzamido-1-phenyl3piperidinopropane Fifty g. of crystalline l-benzamido-l-phenyl-S-piperidinopropane hydrochloride were shaken with a mixture of 200 ml. of ether and 200 ml. of dilute aqueous am- The ether layer containing the free base was dried over anhydrous magnesium sulfate and the ether was removed by distillation. The residue was dissolved in about 100 ml. of hot ethyl acetate and petroleum ether was added until crystallization occurred. The

crystalline precipitate of 1-benzamido-1-phenyl-3-piperidinopropane after recrystallization from a mixture of ethyl 4 acetate and petroleum ether melted at about 111-112 C. Analysis.-Calculated for CziHaaNzOz N, 8.09. Found: N, 8.25.

EXAMPLE 3 Preparation of l-benzamido-Z-methyl-l-phenyl-3-piperidinopropane hydrochloride a-Methyl-fi-piperidinopropiophenone prepared according to the method of Ruddy, J. A. C. S. 72, 718 (1950), was condensed with hydroxylamine to form u-methyl-fipiperidinopropiophenone oxime. The oxime was reduced with Raney nickel according to the procedure of Example 1 to form 1-phenyl-2-methyl-3-piperidinopropylamine.

1-phenyl-2-methyl-3-piperidinopropylamine thus prepared boiled at about 128l29 C. at a pressure of 0.5 mm. of mercury. The index of refraction at 25 C. was

Analysis.-Calculated for C15Hz4N2: N, 12.06. Found: N, 12.18.

A mixture of 9.7g. of 1-phenyl-2-methyl-3-piperidinopropylamine, 9.7 ml. of benzoyl chloride, 20 ml. of dry pyridine and ml. of benzene was allowed to stand for about sixteen hours at room temperature. A suflicient amount of ethyl ether was added to the reaction mixture to bring about a complete precipitation of l-benzamido- 1- phenyl-2- methyl-3- piperidinopropane hydrochloride formed in the reaction. The precipitate was separated, and after recrystallization from a mixture of ethyl acetate and methanol, the 1-benzamido-l-phenyl-2-methyl- 3-piperidinopropane hydrochloride melted at about 262 263 0., with decomposition.

Analysis.Calculated for CzzHzsNzOCl: N, 7.51; Cl, 9.51. Found: N, 7.46; Cl, 9.40.

lbenzamido-lphenyl- 2- methyl- 3- piperidinopropane was prepared from l-benzamido-l-phenyl-2-methyl-3- piperidinopropane hydrochloride by the procedure of Example 2.

EXAMPLE 4 Preparation of 1 4 -cycl0h exyloxy benzamido) -phenyl- 3-piperidin0propane hydrochloride l-phenyl-3-piperidinopropylamine was prepared according to the process of Example 1. A mixture of 5.8 g. of 4-cyclohexyloxybenzoy1 chloride, 8 ml. of pyridine, 4 g. of l-phenyl-3-piperidinopropylamine and 50 ml. of benzene was warmed on a steam bath for about one hour. The reaction mixture was cooled, and sufficient ether was added to bring about complete precipitation of the 1-(4- cyclohexyloxybenzamido) lphenyl-3- piperidinopropane hydrochloride formed in the reaction. The precipitate was removed and recrystallized from a mixture of isopropanol and ether and then from a mixture of methanol and ethyl acetate. The l-(4'-cyclohexyloxybenzamido)-lphenyl-3-piperidinopropane hydrochloride thus prepared melted at about l83-l84 C.

Analysis.Calculated for cz'zHasNzOz-HCl: N, 6.13; Cl, 7.76.- FoundiN, 6.28; CI, 7.66.

By subjecting 1-(4-cyclohexyloxybenzamido)-l-phenyl- 3-piperidinopropane hydrochloride to the procedure of Example 2; there was obtained l-(4' cyclohexyloxybenzamido)-I-phenyl-3-piperidinopropane.

EXAMPLE 5 Preparation of 1- (4'-cyclohexyloxybenzamido) -J-phenyl- 2-methyl-3-piperidirzopropane hydrochloride by filtration and was crystallized from ethyl acetate,

. 5 whereupon 1-(4'-cyclohexyloxybenzamido)-1-phenyl-2- methyl-3-piperidinopropane hydrochloride was obtained, melting at about 220-221 C. with decomposition.

Analysis.-Calcu1ated for CzaHssNzOz-HCI: Cl, 7.53. Found: Cl, 7.31.

1 (4' cyclohexyloxybenzamido) 1 phenyl 2 methyl-3-piperidinopropane base Was prepared from 1 (4 cyclohexyloxybenzamido) -1 phenyl 2 methyl-3-piperidinopropane hydrochloride by the procedure of Example 2.

EXAMPLE 6 Preparation of 1-benzamid0-1-phenyl-3- piperidinopropane maleate To a solution of 32.2 g. of l-benzamido-l-phenyl-3- piperidinopropane (prepared according to the procedure of Example 2) in 100 ml. of ethanol is added a solution of 3.8 g. of maleic acid in 10 ml. of ethanol. The solution is thoroughly mixed, and evaporated to dryness in vacuo, whereby the maleic acid salt of l-benzamidodphenyl-3-piperidinopropane is recovered.

By following the above-described procedure, except that sulfuric acid, citric acid, phosphoric acid, lauric acid, acetic acid and butyric acid are used, the sulfate, citrate, phosphate, laurate, acetate and butyrate salts of 1-benz- 6 t amido-1phenyl-3-piperidinopropane, respectively, are recovered.

I claim:

1. A compound selected from the group consisting of l-benzamido-1-phenyl-2-methy1-3-piperidinopropane, represented by the formula:

and acid addition salts thereof. I 2. 1 benzamido 1 phenyl 2 methyl 3 piperidinopropane, represented by the formula:

No references cited. 

1. A COMPOUND SELECTED FROM THE GROUP CONSISTING OF 1-BENZAMIDO-1-PHENYL-2-METHYL-3-PIPERIDINOPROPANE, REPRESENTED BY THE FORMULA: 